1. Field of the Invention
The present invention relates to an imprint apparatus, and to an article manufacturing method employing the same.
2. Description of the Related Art
As the demand for microfabrication of semiconductor devices or MEMS increases, not only a conventional photolithography technology but also a microfabrication technology in which an uncured resin on a substrate (wafer) is molded by a mold to thereby form a resin pattern on the substrate have been receiving attention. This technology is also referred to as an “imprint technology”, by which a fine structure with dimensions of a few nanometers can be formed on a substrate. One example of imprint technologies includes a photo-curing method. With imprint apparatuses adopting this photo-curing method, first, an ultraviolet-curing resin (imprint material, photo-curing resin) is applied to a shot which is a pattern formation region on the substrate. Next, this resin (uncured resin) is molded with a mold. A resin pattern is then formed on the substrate by withdrawing the mold after the resin is cured by irradiation with ultraviolet light.
With conventional imprint apparatuses adopting the aforementioned imprint technology, it takes a long time for the resin to fill the miniature textured pattern of the patterned portion formed on the mold, and the product may be affected when filling is inadequate. So as to efficiently and satisfactorily fill the patterned portion with resin, Published Japanese Translation No. 2011-505270 of the PCT International Application discloses an imprint apparatus in which a gas (e.g., an inert gas such as helium) is supplied to an interstice between a mold and a substrate when pressing the mold (patterned portion) against the resin on the substrate. In the case where the gas that is supplied at this time is helium, the concentration of gas in the aforementioned interstice is preferably 90% or more from the standpoint of throughput and yield.
Now, even with the imprint apparatus shown in Published Japanese Translation No. 2011-505270 of the PCT International Application, it is necessary to measure the concentration of the gas supplied to the aforementioned interstice with a measuring instrument to confirm whether the gas concentration is appropriate. However, as the size of conventional measuring instruments for measuring gas concentration in an interstice in this manner is large, it is difficult to incorporate such a measuring instrument into the apparatus.